In the related art, for example, as a pressure sensor (differential pressure sensor) which detects variation in pressure, a pressure sensor is known which includes an accommodation container having vent holes, a substrate which is disposed in the accommodation container and includes through holes or recessed portions, and a piezoelectric element which is vibratingly supported by the substrate in a cantilever manner in the through holes or recessed portions (for example, refer to PTL 1).
According to the pressure sensor, the piezoelectric element vibrates according to variation in pressure transmitted to the accommodation container via the vent holes, and a magnitude of a difference in pressure between this pressures and a pressure inside the through holes or the recessed portions following the variation in pressure. As a result, the pressure sensor can detect the variation in pressure transmitted to the accommodation container on the basis of a voltage change generated in the piezoelectric element.